1. Field of the Invention
The present invention relates to a copying lens of completely symmetric configuration, and more particularly to a copying lens having a half angle of view exceeding 40.degree..
2. Description of the Prior Art
Copying machines, electrostatic copiers, and the like are becoming smaller in size, and there are demands for lenses of a wider angle of view for use in such copying machines. Copying lenses of wide angles of view which have heretofore been developed have half angles of view up to about 34.degree.. If an original of an A3 size is to be copied by a copying machine of the full exposure type that incorporates such a copying lens, the congugate length is too long, and the optical path must be bent by a mirror or the like. This had led to a cost increase and prevented the copying machine from being designed for a smaller size.
Japanese Laid-Open Patent Publication No. 55 (1980)-90930, for example, discloses a copying lens comprising eight lens elements. The disclosed copying lens has a half angle of view which is about 20.degree.. If the half angle of view were increased up to 40.degree., the curvature of field would be highly increased, and the lens would not have good performance.